Container manufacturing method, mold, and container

Abstract

To prevent deterioration of appearance quality by easily performing a film insert against a mold core, and preventing a film from being pinched during mold closure.SOLUTION: In a container manufacturing method, a frame mold having an upper part and a lower part with a mold core 20 is used, a cylindrical body film 10 made of a laminate of plastic film is attached to the mold core 20, a molten resin material is injected into the frame mold by insert injection molding means to form a bottom member at an upper end of the body film 10, a frame member is formed at a lower end of the body film 10, a recess 24 extending in a vertical direction is formed at least at the upper and lower ends of a mounting surface of the body film 10 in the mold core 20, a protrusion 25 is formed at a position corresponding to the recess 24 in the frame mold, and the bottom member and the frame member are formed with the body film 10 sandwiched between the recess 24 and the protrusion 25.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a container, a mold, and a container. [Background technology]

[0002] 2. Description of the Related Art Conventionally, cylindrical plastic containers made of a laminate of thin plastic films have been used as containers for storing contents for which preservation is important, such as powdered milk for infants, powdered coffee, coffee beans, and powdered supplements, because they can be reduced in volume after use and are easily disposable.

[0003] For such plastic containers, a method is known in which a body film is inserted into an injection molding die when the plastic container is molded by a film insert method into the die (see, for example, Patent Document 1). That is, the plastic container is cylindrical with a bottom, and has a body molded into a cylindrical shape from a plastic film, and molded parts joined to one end side and the other end side of the body by insert injection molding means. Patent document 1 describes a method in which a laminated tubular member is pushed into the tip end of a mold core, and the laminated tubular member is guided toward the base end of the mold core while gas is sprayed between the mold core and the laminated tubular member, thereby attaching the laminated tubular member to the outer surface of the mold core. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-189682 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional plastic containers have the following problems. In conventional plastic container manufacturing methods such as that described in Patent Document 1, the circumference of the laminated tubular member (body film) made of a plastic laminate film that is attached (inserted) into the mold core is the same as the circumference of the mold core, which can make it difficult to attach the laminated tubular member to the mold core.

[0006] Therefore, if the circumference of the body film was increased (lengthened) to make it easier to attach the body film to the mold, the excess circumference of the body film that adheres to the mold core when the mold is closed would get caught between the mold cores, and wrinkles would occur as the excess part of the body film is pinched between the mold cores, creating a quality problem and leaving room for improvement.

[0007] The present invention has been made in consideration of these circumstances, and its purpose is to provide a container manufacturing method, a mold, and a container that allow the body film to be easily attached to the mold core, and that prevents the film from getting pinched when the mold is closed, thereby suppressing deterioration in appearance quality. [Means for solving the problem]

[0008] A first aspect of the container manufacturing method of the present invention is a container manufacturing method that uses a frame mold having an upper mold and a lower mold equipped with a mold core, attaches a tubular body film to the mold core, and injects molten resin material into the frame mold by insert injection molding means to form an upper molded portion at the upper end of the body film and a lower molded portion at the lower end of the body film, characterized in that a recess extending in the vertical direction is formed at least at the upper and lower ends of the mounting surface of the body film on the mold core, a convex portion is formed at a position corresponding to the recess in the frame mold, and the upper molded portion and the lower molded portion are formed with the body film sandwiched between the recess and the convex portion.

[0009] According to the first aspect of the container manufacturing method of the present invention, the perimeter of the body film is greater than the perimeter of the mold core excluding the recessed portion, so that the body film can be easily attached to the mold core. In addition, when the mold is closed, the recess of the mold core and the protrusion on the frame mold side fit together via the body film, so that the body film adheres closely to the recess, and the entire body film can be adhered closely to the mold core without any excess body film in the circumferential direction. This makes it possible to prevent the body film from being pinched when the mold is closed as in the past, and allows the upper and lower molded portions to be formed with good quality at the top and bottom ends of the body film, thereby preventing any deterioration in the appearance quality of the container.

[0010] A second aspect of the present invention may be characterized in that in the container manufacturing method of the first aspect, the recess is provided over the entire length of the mold core in the up-down direction.

[0011] In this case, the body film of the formed container can be easily pulled out from the mold core in the vertical direction, and therefore, a simple configuration can be achieved in which the mold core is pulled out from the body film in one direction, which simplifies the mold and reduces manufacturing costs.

[0012] In a third aspect of the present invention, in the method for manufacturing a container according to the first or second aspect, it is preferable that the mold surface on which the protrusion is formed moves in a direction perpendicular to the mounting surface.

[0013] In this case, the convex portion of the frame mold can be abutted from a direction perpendicular to the concave portion extending in the vertical direction of the mold core, so that the body film can be securely attached to the concave portion when the mold is closed.

[0014] A fourth aspect of the present invention is a method for producing a container according to any one of the first to third aspects, wherein the mold core has a rectangular cross section.

[0015] In this case, the mounting surface of the rectangular mold core for the body film is flat, and a recess can be formed on this flat mounting surface, so that the protrusion of the frame mold can be easily and reliably engaged with the recess when the mold is closed.

[0016] A fifth aspect of the mold according to the present invention is a method for manufacturing a container according to any one of the first to fourth aspects, in which the recesses are preferably formed in two opposing side surfaces of the four mounting surfaces.

[0017] In this case, with a simple structure in which the convex portions of a frame mold engage with the concave portions of the two opposing side portions on both sides of the mold core, the body film can be attached uniformly in the circumferential direction around the mold core, allowing the production of high-quality containers with excellent appearance.

[0018] A sixth aspect of the present invention may be characterized in that in the method for manufacturing a container according to any one of the first to fourth aspects, the recesses are formed in each of the four mounting surfaces.

[0019] In this case, the convex portions of the frame mold engage with the concave portions of all four mounting surfaces, allowing the body film to be attached uniformly in the circumferential direction to the mold core, producing high-quality containers with excellent appearance.

[0020] A seventh aspect of the present invention may be characterized in that, in the container manufacturing method of any one of the first to sixth aspects, the upper molding portion is formed in a state in which a bottom film is placed on the top surface of the mold core.

[0021] In this case, the upper mold can be closed to attach the bottom film to the top surface of the mold core to form the upper forming portion.

[0022] Aspect 8 of the present invention may be characterized in that, in the method for manufacturing a container according to any one of aspects 1 to 7, the connection portion connecting the body film in the circumferential direction and the recess are positioned at circumferentially offset positions.

[0023] In this case, the connection portion of the body film and the recess do not overlap, so that the convex portion can be engaged with the recess while the body film is sandwiched between them, and the body film can be attached to the mold core over the entire circumferential direction.

[0024] A ninth aspect of the mold of the present invention comprises a frame mold having an upper mold and a lower mold, the lower mold having a mold core onto which a tubular body film is attached, the frame mold having a resin injection section that injects molten resin material by insert injection molding means to form an upper molded portion at the upper end of the body film and a lower molded portion at the lower end of the body film, the mold core having a recess extending in the vertical direction at least at the upper and lower ends of the mounting surface of the body film, and the frame mold having a protrusion at a position corresponding to the recess, the upper molded portion and the lower molded portion being configured to be formable with the body film sandwiched between the recess and the protrusion.

[0025] According to the ninth aspect of the mold of the present invention, when inserting the body film into the mold core, the body film is formed to have a circumferential length that does not fit the mold core along the recessed portion. In other words, since the circumferential length of the body film is larger than the circumferential length of the mold core excluding the recessed portion, the film can be easily inserted into the mold core. In addition, when the mold is closed, the convex part on the frame mold side is sandwiched in the concave part of the mold core with the body film, so that the body film is tightly adhered to the concave part, and the entire body film can be tightly adhered to the mold core without any excess body film in the circumferential direction. Therefore, it is possible to prevent the body film from being sandwiched when the mold is closed as in the past, and it is possible to form high-quality upper and lower molded parts at the upper and lower ends of the body film, and it is possible to suppress deterioration in the appearance quality of the container. It is possible to provide a container that can obtain the above-mentioned effects.

[0026] A tenth aspect of the container according to the present invention is characterized in that the container is produced by the method for producing a container according to any one of the first to eighth aspects.

[0027] According to the tenth aspect of the method for producing a container according to the present invention, a container that can achieve the above-mentioned effects can be provided.

[0028] An eleventh embodiment of the container according to the present invention is characterized in that it is produced using the mold of the ninth embodiment.

[0029] According to the eleventh aspect of the method for producing a container according to the present invention, a container that can obtain the above-mentioned effects can be provided. Effect of the Invention

[0030] The container manufacturing method, mold, and container of the present invention allow for easy film insertion into the mold core, and prevent the film from being pinched when the mold is closed, thereby suppressing deterioration in appearance quality. [Brief description of the drawings]

[0031] [Figure 1] FIG. 2 is a perspective view showing an example of a container body of a container according to an embodiment of the present invention. [Diagram 2] 2 is a perspective view of the container body shown in FIG. 1 as viewed from the bottom side. [Diagram 3] FIG. 2 is a view taken along line II in FIG. 1, and is a side view of a container body. [Figure 4] FIG. 2 is a view taken along line II-II in FIG. 1, and is a side view of a container body. [Diagram 5] 2 is a plan view of the container body shown in FIG. 1 as viewed from the upper end portion. [Figure 6] FIG. 2 is a side view of a mold for manufacturing the container body, showing the mold closed state. [Figure 7] FIG. 4 is a plan view showing a state in which the slide mold is opened. [Figure 8] 13 is a plan view showing a state in which only the slide insert portion of the slide mold is closed. FIG. [Figure 9] 13 is a plan view showing the state in which the slide insert portion and the slide mold closing portion of the slide mold are closed. FIG. [Figure 10] 7(a) to 7(c) are side views showing a process of attaching a body film to the mold shown in FIG. [Figure 11] FIG. 7 is a side view of the mold shown in FIG. 6, showing a state in which the mold is opened. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Hereinafter, embodiments of the container manufacturing method, the mold, and the container according to the present invention will be described with reference to the drawings. Note that in each drawing, the scale of each component may be appropriately changed as necessary to make each component large enough to be visible.

[0033] The manufacturing method of the container 1 of this embodiment shown in Figures 1 to 5 uses a frame mold 2A having an upper mold 21 and a lower mold 22 equipped with a mold core 20, as shown in Figures 6 to 11, and a tubular body film 10 consisting of a laminate of plastic films is attached to the mold core 20. Molten resin material is injected into the frame mold 2A (upper mold 21 and lower mold 22) by insert injection molding means to form a bottom member 13 (upper molded portion) at the upper end (upper opening end 10a) of the body film 10 and a frame member 12 (lower molded portion) at the lower end (lower opening end 10b).

[0034] <Container configuration> Here, the container 1 to be manufactured will be described with reference to Fig. 1 to Fig. 5. The container 1 comprises a container body 1A and a lid member (not shown) fitted to an upper opening end 10a of the container body 1A. The body portion of the container 1 is formed from a body film 10 made of a laminated film constituted by a plastic film or the like.

[0035] The container 1 is a container for storing powders such as powdered milk for babies, powdered coffee, and powdered supplements, or granular materials such as rice and coffee beans. The container 1 may also be a container for storing paste-like contents such as miso paste or jam, or liquids. The contents of the container 1 are not limited to food, and may be daily necessities such as detergents and caulking materials.

[0036] The container 1 is substantially rectangular parallelepiped (substantially square prism). Note that the shape of the container 1 is not limited to a rectangular parallelepiped, and may be, for example, cylindrical or substantially polygonal prism other than a square prism.

[0037] Here, in this embodiment, the die core 20 of the die 2 is formed into a cylindrical shape with a rectangular cross section, and the die axis passing through the center of the cross section is called the die axis O, the direction along the die axis O is called the axial direction, and along the die axis O, the lower die 22 side is called the lower side, and the upper die 21 side is called the upper side. Also, in a plan view seen from the axial direction, the direction perpendicular to the die axis O is called the radial direction, and the direction going around the die axis O is called the circumferential direction.

[0038] <Container body> 1 and 2, the container body 1A includes a body member 11, a frame member 12 provided at the upper end of the body member 11, and a bottom member 13 provided at the lower end of the body member 11. The container body 1A has an upper end that forms a lower opening end 10b that is open, and a lower end that forms an upper opening end 10a that is closed by the bottom member 13.

[0039] The body member 11 is a cylindrical body having an upper opening end 10a and a lower opening end 10b. As will be described later in the manufacturing method of the container body 1A, the body member 11 is formed into a cylindrical shape, for example, by enveloping the circumferential ends of a rectangular body film 10.

[0040] Furthermore, body member 11 can stand on its own in a cylindrical state when upper open end 10a or lower open end 10b is placed on a flat surface. Here, "stand on its own" means that body member 11 is formed into a cylindrical or bag-like shape using body film 10, and has sufficient rigidity to maintain a self-supporting state without buckling or deforming due to its own weight.

[0041] The body film 10 is composed of a laminate having, for example, a heat-sealed layer that forms the outer peripheral surface of the body member 11, an intermediate layer that imparts predetermined strength and gas barrier properties to the body film 10, and a heat-sealed layer that forms the inner peripheral surface of the body member 11. The layers of this laminate are bonded together by an adhesive layer. This laminate structure of the body film 10 is one example and can be modified as appropriate.

[0042] The heat-sealing layer is a layer that can be heat-sealed. This allows the heat-sealing layer to adhere to the frame member 12 and the bottom member 13. The heat-sealing layer is a plastic film formed of a resin material such as low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (L-LDPE), or polypropylene (PP). The heat-sealing layer is preferably an unstretched film made of these resin materials. Alternatively, the heat-sealing layer may be a multi-layer film obtained by co-extrusion of these resin materials or other resin materials. The thickness of the heat-sealing layer is preferably in the range of 10 to 200 μm, more preferably 20 to 150 μm.

[0043] The intermediate layer is provided between the heat-sealing layers, and preferably has puncture strength, tensile strength, impact resistance, and the like in addition to excellent printability. The intermediate layer is a plastic film formed of a resin material such as polyester, such as medium density polyethylene (MDPE), high density polyethylene (HDPE), polyethylene terephthalate (PET), or polybutylene terephthalate (PBT), polypropylene (PP), polyamide (PA), or ethylene vinyl alcohol copolymer (EVOH). The intermediate layer may be either a stretched film or an unstretched film made of the above material. The thickness of the intermediate layer is preferably in the range of 4 to 50 μm, and more preferably 7 to 30 μm.

[0044] The intermediate layer may be, for example, a metal foil made of aluminum, magnesium, iron, copper, or the like, a vapor-deposited film on which a metal such as aluminum or magnesium or an oxide such as silicon oxide is vapor-deposited, or a coated film coated with a barrier coating agent such as polyvinylidene chloride. By providing any of these in the intermediate layer, gas barrier properties can be imparted to the body film 10. The intermediate layer may be a multi-layered plastic film obtained by co-extrusion of a combination of multiple resin materials. The intermediate layer may be composed of one layer, or may be composed of two or more layers.

[0045] The body member 11 is not limited to a single body film 10 formed into a cylindrical shape by enveloping or the like. For example, the body member 11 may be formed into a cylindrical shape by folding the back-pasted portion, which is formed by heat-sealing the back surfaces (inner surfaces) of the left and right ends of a single rectangular body film, toward the body member, or by heat-sealing the opposing edges of two rectangular body films, or may be a cylindrical body formed by cutting a tube made of a single-layer or multi-layered plastic film that has been blown into an inflation molded shape to an arbitrary length.

[0046] The body member 11 has a rectangular cross section. A pair of side surfaces of the body member 11 extending in the long axis direction X2 have multiple grooves 14 formed at intervals in the circumferential direction (long axis direction X2) that extend over the entire length in the up-down direction (axial direction). Here, four grooves 14 are formed on each side surface. In the formed container body 1A, by providing the body member 11 with grooves 14 that extend over the entire length in the up-down direction, it is expected that the compression strength of the body member 11 in the direction along the mold axis O will be improved.

[0047] In addition, the above-mentioned recessed groove 14 is not formed in the cylindrical body film 10 before it is manufactured into the container 1 using the mold 2. The circumferential length of the body film 10 is set to be, for example, about 1.2 mm larger than the circumferential length not including the length of the concave inner surface of a recess 24 of the mold core 20 described below. The circumferential length of the body film 10 is set to be approximately the same dimension as the entire circumferential length of the mold core 20 including the length of the concave inner surface of the recess 24. In other words, the circumferential length of the body film 10 is approximately equal to the length at which the body film 10 adheres closely to the mold core 20 without any gaps when the mold is closed and the body film 10 adheres closely to the recess 24 of the mold core 20. If the circumference of the body film 10 is too long compared to the overall circumference of the mold core 20, the excess portion of the body film 10 that has become loose and non-adherent will gather together in the area between the split slide dies 23A, 23B described below, i.e., in the central area in the short axis direction X1 of the mold core 20, and may be cut off by the split slide dies 23A, 23B, causing a defect in which a hole will be created.

[0048] The frame member 12 is provided so as to be joined to the outer peripheral surface of the lower opening end 10b of the body member 11. The frame member 12 reinforces the edge of the lower opening end 10b so that the lower opening end 10b maintains a predetermined opening shape (rectangle, polygon, circle, etc.). The frame member 12 is formed in a first molding space S1 of the mold 2 which will be described later.

[0049] As shown in Figs. 1, 3 and 4, the frame member 12 is composed of a reinforcing portion 121, a flange portion 122 and a fitting portion 123. The reinforcing portion 121 is arranged so as to cover the lower opening end 10b of the body member 11 from the outside, and reinforces the lower opening end 10b. The fitting portion 123 is fitted into a fitting portion (not shown) formed on the lid member when the lid member (not shown) is attached to the container body 1A. The flange portion 122 is arranged between the reinforcing portion 121 and the fitting portion 123, and holds the lid member fitted into the fitting portion 123. The material of the frame member 12 is, for example, low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, or the like.

[0050] 2 and 5, the bottom member 13 is joined to the inner peripheral surface of the lower end of the body member 11 and is formed so as to close the upper opening end 10a of the body member 11. The bottom member 13 closes the lower opening end 10b of the body member 11 in an airtight or liquidtight manner depending on the type and properties of the contents of the container 1. The material of the bottom member 13 is, for example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, or the like.

[0051] <Mold> Next, the mold 2 will be described with reference to Figs. 6 to 11. As shown in Fig. 6, the mold 2 has an upper mold 21 and a lower mold 22 that partially includes a mold core 20. Here, the upper mold 21 and the lower mold 22 correspond to a frame mold 2A. The lower mold 22 includes a slide mold 23. With the body film 10 attached to the mold core 20, the mold 2 is closed with the upper mold 21 and the lower mold 22 that includes the slide mold 23, and resin is further filled in desired locations, thereby forming the frame member 12 and the bottom member 13 shown in Figs. 1 and 2 integrally with the body film 10.

[0052] The slide die 23 provided in the lower die 22 is provided so as to be movable forward and backward by being guided by an upper surface 22a of the lower die 22. The upper surface 22a of the lower die 22 is in contact with the lower surface of the slide die 23 at least around the periphery of the die core 20.

[0053] The mold core 20 is located at the center of the upper surface 22a of the lower mold 22 in a plan view. The mold core 20 has a substantially rectangular cross section (cross section perpendicular to the mold axis O) from the base end to the tip end, and the outer periphery of the mold core 20 is uniform throughout the axial direction. The body film 10 formed in a cylindrical shape is attached to the peripheral wall 20a of the mold core 20 using a transfer jig (not shown). A method of transferring the body film 10 to the mold core 20 using the transfer jig will be described later.

[0054] The mold core 20 has a cylindrical peripheral wall 20a (side surfaces 20aA, 20aB, 20aC, 20aD) having four faces, and a top surface 20b covering the tip of the peripheral wall 20a. A pair of opposing first side surfaces 20aA, 20aB constituting the long side of the peripheral wall 20a of the mold core 20 each have a plurality of recesses 24 formed in the circumferential direction, each extending over the entire vertical direction (axial direction). Here, four recesses 24 are formed in each of the first side surfaces 20aA, 20aB. In addition, a pair of opposing second side surfaces 20aC, 20aD constituting the short side of the peripheral wall 20a are formed as flat surfaces without any irregularities. The recesses 24 are provided to form the recessed grooves 14 (see FIG. 1 and FIG. 2) formed in the body film 10 described above.

[0055] The total perimeter, including the length of the concave inner surface of the recesses 24 in the mold core 20, is set to approximately the same dimension as the perimeter of the body film 10. That is, the total length of the concave inner surfaces of all (eight in this case) recesses 24 formed in the mold core 20 is set to the same dimension as the above-mentioned excess length (e.g., approximately 1.2 mm) of the body film 10. As a result, when the body film 10 is closed, the body film 10 is attached in a state of intimate contact with the mold core 20.

[0056] The slide die 23 has split slide dies 23A and 23B that are split in two in the minor axis direction X1 of the die core 20 with the die axis O of the die core 20 in between. That is, the split slide dies 23A and 23B are provided so as to be movable forward and backward in the minor axis direction X1. The slide die 23 covers the entire peripheral wall portion 20a of the die core 20 from the outside when the die is closed.

[0057] As shown in FIGS. 7 to 9, each of the split slide dies 23A and 23B has a slide insert portion 231 and a slide die closing portion 232.

[0058] The slide insert part 231 is disposed at the center of the slide mold closing part 232 in the long axis direction X2 of the mold core 20, and is provided so as to be relatively movable in the short axis direction X1 with respect to the slide mold closing part 232. The slide insert part 231 has a first mold closing surface 231a that faces only the first side surfaces 20aA, 20aB of the mold core 20. On the first mold closing surface 231a, a plurality of convex parts 25 (the same number as the concave parts 24) are formed at intervals in the long axis direction X2 and are provided so as to be engageable with a plurality of concave parts 24 formed on the first side surfaces 20aA, 20aB. The protruding height of the convex parts 25 is preferably, for example, 0.5 to 2.5 mm, more preferably 0.7 to 1.5 mm, and further preferably 1.0 to 1.2 mm, similar to the concave depth of the concave parts 24. During mold closing, the slide insert portion 231 abuts the first mold closing surface 231 a against the first side surfaces 20 aA, 20 aB of the mold core 20 prior to the slide mold closing portion 232 .

[0059] The slide mold closing portion 232 is movable in the minor axis direction X1 relative to the slide insert portion 231. The slide mold closing portion 232 has a second mold closing surface 232a that contacts from the corner portion of the mold core 20 to the second side surfaces 20aC, 20aD. When closing the mold, the slide mold closing portion 232 abuts the second mold closing surface 232a from the corner portion of the mold core 20 against the second side surfaces 20aC, 20aD after the mold is closed by the slide insert portion 231.

[0060] As shown in Fig. 6 and Fig. 7, a space corresponding to the shape of the frame member 12 (see Fig. 1) to be molded on the lower opening end 10b of the body film 10 is formed on the inner surface of the slide insert portion 231 of the divided slide molds 23A and 23B, and when the slide mold 23 is in the mold closing position with respect to the lower mold 22 (mold core 20), a first molding space S1 for forming the frame member 12 is formed between the base end of the mold core 20 and the upper surface 22a of the lower mold 22. This first molding space S1 communicates with a resin injection section (not shown) for filling with molten resin provided in the slide mold 23. This allows molten resin to flow into the first molding space S1. The molten resin is filled into the first molding space S1 and hardened, so that the frame member 12 is integrally joined to the lower opening end 10b of the body film 10.

[0061] As shown in FIG. 6 and FIGS. 10(a) to (c), a tapered surface 23b that is gradually reduced in diameter from bottom to top is formed on the outer periphery of the split slide dies 23A and 23B. Furthermore, a positioning hole 233 is formed on the upper surface 23c of the split slide dies 23A and 23B along the tapered surface 23b. The positioning hole 233 is provided so that a positioning pin 213 provided on the upper die 21 can be inserted into the positioning hole 233. When the upper die 21 approaches the lower die 22 in the axial direction and the positioning pin 213 of the upper die 21 is inserted into the positioning hole 233, the pair of split slide dies 23A and 23B move in a direction approaching each other (die closing direction). That is, the slide die 23 is also closed at the same time as the upper die 21 moves.

[0062] The upper die 21 is provided so as to be movable forward and backward in the axial direction relative to the die core 20 of the lower die 22. The upper die 21 has a base portion 211 and an outer peripheral frame 212 protruding downward from the base portion 211. The outer peripheral frame 212 is an outer peripheral side wall formed over the entire circumference in the circumferential direction. A tapered surface 21b is formed on the inner peripheral portion of the outer peripheral frame 212, the diameter of which gradually increases from top to bottom. A bottom surface (lower surface) 212a is formed on the inside of the outer peripheral frame 212.

[0063] Further, a positioning pin 213 is formed on the lower surface of the base portion 211 along the tapered surface 21b. The positioning pin 213 is provided so as to be insertable into a positioning hole 233 formed in the slide mold 23. When the upper mold 21 approaches the lower mold 22 in the axial direction and the positioning pin 213 of the upper mold 21 is inserted into the positioning hole 233, the pair of split slide molds 23A, 23B move in a direction approaching each other (mold closing direction).

[0064] As shown in Fig. 6, when the upper mold 21 is in the mold closing position relative to the mold core 20, a second molding space S2 corresponding to the shape of the bottom member 13 (see Fig. 2) to be molded on the upper opening end 10a of the body film 10 is formed between the top surface 20b of the mold core 20 and the lower surface 212a of the outer peripheral frame 212 of the upper mold 21. This second molding space S2 communicates with a resin injection section (not shown) for filling with molten resin, which is provided in the upper mold 21. This allows molten resin to flow into the second molding space S2. The molten resin is filled into the second molding space S2 and hardened, whereby the bottom member 13 is integrally bonded to the upper opening end 10a of the body film 10.

[0065] <Container manufacturing method> Next, a method for producing the container 1 using the above-mentioned mold 2 will be specifically described with reference to FIGS. First, a laminate film is used to form a cylindrical body film 10. For example, the body film 10 is formed by overlapping the ends of a rectangular laminate film and sealing it into an envelope.

[0066] Figures 10(a) to (c) are side views showing the process of attaching body film 10 to mold 2. Figure 10(a) shows a mold open state in which upper mold 21 and lower mold 22 are separated. Figure 10(b) shows a state in which body film 10 is waiting above mold core 20, held by a delivery jig (not shown). Figure 10(c) shows a state in which body film 10 has been attached to mold core 20.

[0067] Next, as shown in FIG. 10(a), the mold 2 is opened. That is, in the open state, the upper mold 21 and the slide mold 23 are separated from the lower mold 22 having the mold core 20. Then, as shown in FIG. 10(b), the mold 2 is opened, and the cylindrical body film 10 held by a transfer jig (not shown) above the mold core 20 is made to wait. Then, as shown in FIG. 10(c), the waiting body film 10 is attached so as to cover the mold core 20. In this case, if the body film 10 is molded in a rectangular cylindrical shape in advance, the attachment to the mold core 20 can be performed smoothly, but it is not essential to mold the body film 10 in a rectangular cylindrical shape in advance. If the body film 10 is at least formed in a cylindrical shape, the attachment to the mold core 20 can be performed smoothly.

[0068] At this time, the body film 10 does not have the recessed groove 14 formed therein, and so is attached to the mold core 20 with a slight gap therebetween. In other words, the circumferential length of the body film 10 is set to be slightly larger than the circumferential length of only the outer periphery, not including the inner periphery of the recessed portion 24 of the mold core 20, so that the body film 10 can be easily attached to the mold core 20.

[0069] Next, as shown in Figures 7, 8 and 11, the upper mold 21 is lowered and the positioning pin 213 of the upper mold 21 is inserted into the positioning hole 233 of the slide mold 23, thereby moving the pair of split slide molds 23A, 23B toward the mold core 20 in the short axis direction X1. 8, the slide insert portion 231 is first moved toward the mold core 20, and the first mold closing surface 231a is brought into contact with the first side surfaces 20aA, 20aB of the mold core 20 with the body film 10 sandwiched between them. At this time, the convex portions 25 of the first mold closing surface 231a engage with the concave portions 24 of the first side surfaces 20aA, 20aB. As a result, the concave grooves 14 are formed in the body film 10 located on the first side surfaces 20aA, 20aB.

[0070] 9, the slide mold closing portion 232 is moved toward the mold core 20, and the second mold closing surface 232a is brought into contact with the second side surfaces 20aC, 20aD of the mold core 20 while sandwiching the body film 10. At the same time, the upper mold 21 also moves downward, as shown in FIG. 6, and mold closing is completed.

[0071] When the mold closing is completed, molding spaces S1 and S2 are formed between the body film 10 and the mold 2. Specifically, a first molding space S1 is formed between the base end of the mold core 20 and the upper surface 22a of the lower mold 22. A second molding space S2 is formed between the lower surface 212a of the outer peripheral frame 212 of the upper mold 21 and the top surface 20b of the mold core 20. In the next step, a synthetic resin material is injected in a molten state into the first molding space S1 and the second molding space S2 by insert injection molding means through a filling flow path (not shown) provided in the mold 2. This forms the frame member 12 and the bottom member 13 that are integrally joined to the body film 10. This produces the container body 1A.

[0072] Next, a method for manufacturing the container 1 thus configured, and the functions of the mold 2 and the container 1 will be described in detail.

[0073] The method for manufacturing a container 1 according to this embodiment uses a frame mold 2A having an upper mold 21 and a lower mold 22 equipped with a mold core 20, a tubular body film 10 made of a laminate of plastic films is attached to the mold core 20, and molten resin material is injected into the frame mold by insert injection molding means to form a bottom member 13 at the upper end of the body film 10 and a frame member 12 at the lower end. In the method for manufacturing a container 1, recesses 24 extending in the vertical direction are formed at least at the upper and lower ends of the attachment surface of the body film 10 on the mold core 20, and protrusions 25 are formed in the frame mold at positions corresponding to the recesses 24, and the bottom member 13 and frame member 12 are formed with the body film 10 sandwiched between the recesses 24 and the protrusions 25.

[0074] Moreover, the mold 2 according to this embodiment includes a frame mold 2A having an upper mold 21 and a lower mold 22. The lower mold 22 includes a mold core 20 to which a cylindrical body film 10 made of a laminate of plastic films is attached. The frame mold 2A includes a resin injection section that injects molten resin material by insert injection molding means to form a bottom member 13 at the upper end of the body film 10 and a frame member 12 at the lower end. The mold core 20 has recesses 24 extending in the vertical direction at least at the upper and lower ends of the attachment surface of the body film 10, and the frame mold has protrusions 25 at positions corresponding to the recesses, and is provided so that the bottom member 13 and the frame member 12 can be formed with the body film 10 sandwiched between the recesses 24 and the protrusions 25.

[0075] According to the container manufacturing method of this embodiment, the body film 10 is attached to the mold core 20, and when mold clamping is not complete, the body film 10 is formed along the recess 24 with a circumferential length that does not allow it to come into close contact with the mold core 20. In other words, since the circumferential length of the body film 10 is greater than the circumferential length of the mold core 20 excluding the recess 24, the body film 10 can be easily attached to the mold core 20. Furthermore, when the mold 2 is closed, the recess 24 of the mold core 20 and the protrusion 25 on the frame mold side fit together via the body film 10, so that the body film 10 adheres closely to the recess 24, and no excess body film 10 remains in the circumferential direction, allowing the entire body film 10 to be adhered closely to the mold core 20. This makes it possible to prevent the body film 10 from being pinched when closing the mold as in the conventional method, and allows the bottom member 13 and frame member 12 to be formed with good quality at the upper and lower ends of the body film 10, thereby preventing any deterioration in the appearance quality of the container 1.

[0076] In this embodiment, the recesses 24 are provided over the entire length of the mold core 20 in the vertical direction, which makes it easier to pull the body film 10 of the formed container 1 in the vertical direction from the mold core 20. This allows for a simple configuration in which the mold core 20 is pulled out of the body film 10 in one direction, which simplifies the mold 2 and reduces manufacturing costs.

[0077] Furthermore, in this embodiment, the first mold closing surface 231a (mold surface) on which the convex portion 25 of the frame mold 2A is formed can be moved in a direction perpendicular to the attachment surface, thereby allowing the convex portion 25 of the frame mold to abut from a direction perpendicular to the concave portion 24 extending in the vertical direction of the mold core 20, so that the body film 10 can be securely attached to the concave portion 24 when the mold is closed.

[0078] In this embodiment, by using the mold core 20 having a rectangular cross section, the mounting surface of the rectangular mold core 20 onto which the body film 10 is attached becomes flat, and the recesses 24 can be formed on this flat mounting surface. Therefore, the protrusions 25 of the frame mold can be easily and reliably engaged with the recesses 24 when the mold is closed.

[0079] In this embodiment, the recesses 24 are formed on two opposing side surfaces (first side surfaces 20aA, 20aB) among the four mounting surfaces. Therefore, with a simple structure in which frame-shaped protrusions 25 are engaged with the recesses 24 on the two opposing side surfaces from both sides of the mold core 20, the body film 10 can be uniformly mounted on the mold core 20 in the circumferential direction, and a high-quality container 1 with excellent appearance can be manufactured.

[0080] Furthermore, in this embodiment, the connection portions that connect the laminate in the body film 10 in the circumferential direction and the recesses 24 are positioned at positions that are offset in the circumferential direction. Therefore, the connection portions of the body film 10 and the recesses 24 do not overlap, so that the protrusions 25 can be engaged with the recesses 24 while the body film 10 is sandwiched, and the body film 10 can be attached to the mold core 20 over the entire circumferential direction.

[0081] Furthermore, in this embodiment, since the container 1 is manufactured by the manufacturing method described above, it is possible to provide the container 1 that can obtain the effects described above.

[0082] Furthermore, in this embodiment, since the above-described mold 2 is used for manufacturing, it is possible to provide the container 1 that can obtain the above-described effects.

[0083] In the container manufacturing method, mold, and container of this embodiment configured as described above, the tubular body film can be easily attached to the mold core 20, and the film can be prevented from being pinched when the mold is closed, thereby suppressing deterioration in appearance quality.

[0084] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. The embodiments and their modifications include, for example, those that can be easily imagined by a person skilled in the art, those that are substantially the same, those that are within the scope of the equivalents, and the like.

[0085] For example, in the above embodiment, an example is shown in which the shape of the body film 10 is a tube with a substantially rectangular cross section, but the cross-sectional shape is not limited to being substantially rectangular, and may be, for example, circular.

[0086] In addition, the mold 2 of this embodiment is configured to include a slide mold 23 in the lower mold 22, and a mold is adopted in which the divided slide molds 23A and 23B slide in the minor axis direction X1 relative to the lower mold 22, but is not limited to this type of mold 2. For example, a mold may be configured to omit the slide mold 23. In this case, for example, a convex portion 25 may be provided on a part of the upper mold, and the convex portion 25 may be configured to approach and move away from the concave portion 24 of the mold core 20.

[0087] In this embodiment, the recesses 24 of the mold core 20 may be formed on each of the four mounting surfaces. In this case, the frame-shaped protrusions 25 are engaged with the recesses 24 on all four mounting surfaces, so that the body film 10 can be attached uniformly in the circumferential direction to the mold core 20, improving the quality of the container.

[0088] Furthermore, the recess 24 may be provided on only one of the multiple mounting surfaces of the mold core 20.

[0089] In addition, in this embodiment, the recesses 24 are provided over the entire vertical direction of the mold core 20, but this is not limited to the entirety. In short, it is sufficient that recesses extending in the vertical direction are formed at least on the upper and lower ends of the mounting surface of the mold core 20 on which the body film 10 is attached.

[0090] Furthermore, the shape (depth, width (circumferential length)) and number of the recesses 24 and the shape (height, width (circumferential length)) and number of the protrusions 25 can be set as desired.

[0091] In addition, in this embodiment, a bottom film made of a laminated film having the same configuration as the body film 10 can be placed on the top surface 20b of the mold core 20, the upper mold 21 can be closed, and a molten resin material can be injected into the second molding space S2 by insert injection molding means to form a bottom member 13 (upper molded portion) integrated with the bottom of the body film 10.

[0092] With regard to the components of the body film 10, from the viewpoint of material recyclability, the higher the mono-material ratio (the proportion of a single material) of the body film 10, the better, with 80% or more being preferable, and 90% or more being more preferable. Specifically, polyethylene, polypropylene, or a mixture of polyethylene and polypropylene can be used as the resin material constituting the body film 10. A high mono-material ratio is preferable in that less residue is left during material recycling, making recycling more efficient and reducing the environmental burden. [Explanation of symbols]

[0093] 1 container 1A Container body 2. Mold 2A Frame Type 10 Body film (attachment surface) 10a Upper open end 10b Lower open end 11 Body parts 12 Frame member (lower part) 13 Bottom member (upper forming part) 14 Groove 20 Mold Core 20a Peripheral wall part 20aA, 20aB 1st side 20aC, 20aD 2nd side 20b Top 21 Upper mold 22 Lower mold 23 Slide type 23A, 23B Split Slide Type 231 Slide insert part 231a 1st mold closing surface (mold surface) 232 Slide type closure 232a 2nd mold closing surface 24 Recess 25 Convex O Mold axis S1 1st molding space S2 2nd molding space X1 Short axis direction X2 Long axis direction

Claims

1. A method for manufacturing a container, comprising the steps of: using a frame mold having an upper mold and a lower mold equipped with a mold core; attaching a tubular body film to the mold core; and injecting a molten resin material into the frame mold by an insert injection molding means to form an upper molded portion at an upper end of the body film; and forming a lower molded portion at a lower end of the body film, A recess extending in the vertical direction is formed at least at the upper and lower ends of the mounting surface of the body film in the mold core, a protrusion is formed at a position corresponding to the recess in the frame mold, A method for manufacturing a container, comprising forming the upper molded portion and the lower molded portion in a state in which the body film is sandwiched between the concave portion and the convex portion.

2. The method for manufacturing a container according to claim 1 , wherein the recess is provided over the entire length of the mold core in the vertical direction.

3. The method for manufacturing a container according to claim 1 , wherein the mold surface on which the convex portion is formed moves in a direction perpendicular to the mounting surface.

4. The method for manufacturing a container according to claim 1 , wherein the mold core has a rectangular cross section.

5. The method for manufacturing a container according to claim 4 , wherein the recesses are formed in two opposing side surfaces of the four mounting surfaces.

6. The method for manufacturing a container according to claim 4 , wherein the recess is formed on each of the four mounting surfaces.

7. The method for manufacturing a container according to claim 1 , wherein the upper molding portion is formed in a state where a bottom film is placed on the top surface of the mold core.

8. The method for manufacturing a container according to claim 1 , wherein a connection portion that connects the body film in a circumferential direction and the recess are disposed at positions offset from each other in the circumferential direction.

9. A frame mold having an upper mold and a lower mold is provided, The lower mold includes a mold core to which a cylindrical body film is attached, the frame mold is provided with a resin injection section for injecting a molten resin material by insert injection molding means to form an upper molding section at an upper end of the body film and a lower molding section at a lower end of the body film, The mold core has a recess extending in the vertical direction at least at the upper and lower ends of the mounting surface of the body film, The frame mold has a protrusion at a position corresponding to the recess, A mold characterized in that the upper molding portion and the lower molding portion are formed in a state in which the body film is sandwiched between the concave portion and the convex portion.

10. A container manufactured by the method for manufacturing a container according to any one of claims 1 to 8.

11. A container manufactured using the mold according to claim 9.

Images